The manufacture of memory, such as non-volatile memory in an integrated circuit begins with generating a circuit layout from a design specification for the memory, determining exposure conditions from the circuit layout, and designing an exposure mask that corresponds to the exposure conditions. The exposure mask is then used to perform photolithography and etching to form each layer structure such as a semiconductor layer, interconnection layer, and the like thereby completing the memory.
In recent years, in conjunction with higher density of integrated circuits, optimizing the exposure conditions and processing conditions have become critical. For example, when designing the exposure mask to optimize exposure conditions and processing conditions used by the exposure mask, it often becomes necessary to change the design specification. In the manufacture of an integrated circuit, it is important that optimal exposure conditions and processing conditions that match the design specification are obtained in a short period of time.